Belt drive systems are commonly employed to transmit rotational power between two or more shafts. Typically, each shaft includes a sheave defining a circumferential groove in which the belt may ride. Depending on the application, the belt may be selectively tightened about the sheaves to transmit power, or slackened to reduce frictional engagement with the sheaves, e.g., to stop power transmission. Loosening of the belt may be accomplished via any number of ways including moving the shafts relatively to each other or by using a tensioning idler or a clutch.
When the belt is in its slackened position, it is important to ensure that, although loose, it does not separate completely from the sheave groove. Otherwise, re-engagement of the system (re-tensioning of the belt) may be problematic as the belt may not draw into the sheave groove and re-engage as desired.
To ensure proper belt positioning when the belt is slack, various retaining devices are known. Often these devices are constructed as wire form brackets that bolt to structure and have surfaces that sit in close proximity to the sheave just beyond the sheave periphery. These devices may be positioned to interfere with the slackened belt and ideally prevent the belt's complete exit from the sheave groove when slackened. Other belt retainers may utilize multiple rigid members that function similarly and may be attached along the periphery of the sheave.
While effective, these retainers often include numerous pieces and may require repositioning/removal, with the assistance of tools, to penult belt removal/replacement. Moreover, some of these retainer configurations may require periodic adjustment to ensure desired performance.